Infernal master + Doombolt

I know that this subject has been discussed a lot on here, but can anyone definitively say that you can/cannot use the infernal masters auto 6 for the D3+N on their doombolt? Even better, does someone have an FAQ or an official ruling to put the conversation to bed?

My friend plays Thousand Sons and we have (friendly) debates about this very often. My instict tells me that GW didn't design it to allow for that, however I can't find a definition within the rules that clearly distinguishes the damage roll here from other damage rolls.

EDIT: After looking at the comments and thinking about it a bit more I now think that the word 'characteristic' settles it. A 'Damage roll' is defined in the rules as: “When determining a random Damage characteristic, the dice roll made is called a Damage Roll”, as someone kindly pointed out. 'Characteristic' is only ever used to describe a field that appears within unit and weapon profiles. Therefore, the D3 within doombolt is not a damage characteristic and is not a 'Damage Roll'. If someone can find an instance of the word characteristic being used in a context NOT referring to a field within a unit/weapon profile, then I'll concede that you can use the ability for doombolt.